1. Field of the Invention
This invention relates to a noise-controlled circular saw blade.
2. Prior Art Relating to the Disclosure
Circular saw blades have generally been designed with primary regard to cutting ability, performance and blade life with little or no regard for the noise created by the blade when in operation. With the increasing knowledge about the detrimental effects of high noise levels on working personnel, laws and regulations are being implemented to control and reduce noise levels. In mills where sawing is carried out, the noise levels are generally at a high level. The noise level can be controlled in a number of ways, such as requiring the workers to wear noise protectors. No real effort, however, has been put into developing saw blades having reduced noise levels.
Circular saws in predominant use today have gullets which are wide, deep and of generally round construction. They also generally include curved shoulders behind the teeth. Saw noise is generated from many sources -- the saw blades, the saw enclosure, saw guards, etc. The saw blades themselves generate two distinctly different types of noise -- free spinning noise and cutting noise. The free spinning noise is a combination of (1) air noise and (2) saw plate vibration. Most of the free spinning noise is air generated with this air generated noise then picked up and amplified by vibration in the saw plate.
Through experimentation it has been found that the conventional tooth and gullet shapes are the principal cause of free spinning saw noise. Knowing this, it has remained a problem to design tooth forms which reduce the noise level of a free spinning circular saw blade to acceptable levels.